关于图片相关处理代码片段

图片工具类， 图片水印，文字水印，缩放，补白等

• 添加图片水印
• 添加文字水印
• 检查传入file的format名称
• 获取字符长度
• 图片缩放

---

添加图片水印

/**
     * 添加图片水印
     * @param targetImg 目标图片路径，如：C://myPictrue//1.jpg
     * @param waterImg  水印图片路径，如：C://myPictrue//logo.png
     * @param x 水印图片距离目标图片左侧的偏移量，如果x<0, 则在正中间
     * @param y 水印图片距离目标图片上侧的偏移量，如果y<0, 则在正中间
     * @param alpha 透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)
    */
    public final static void pressImage(String targetImg, String waterImg, int x, int y, float alpha) {
        try {
            File file = new File(targetImg);
            Image image = ImageIO.read(file);
            int width = image.getWidth(null);
            int height = image.getHeight(null);
            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bufferedImage.createGraphics();
            g.drawImage(image, 0, 0, width, height, null);

            Image waterImage = ImageIO.read(new File(waterImg)); // 水印文件
            int width_1 = waterImage.getWidth(null);
            int height_1 = waterImage.getHeight(null);
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));

            int widthDiff = width - width_1;
            int heightDiff = height - height_1;
            if (x < 0) {
                x = widthDiff / 2;
            } else if (x > widthDiff) {
                x = widthDiff;
            }
            if (y < 0) {
                y = heightDiff / 2;
            } else if (y > heightDiff) {
                y = heightDiff;
            }
            g.drawImage(waterImage, x, y, width_1, height_1, null); // 水印文件结束
            g.dispose();
            ImageIO.write(bufferedImage, PICTRUE_FORMATE_JPG, file);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

添加文字水印

/**
     * 添加文字水印
     * @param targetImg 目标图片路径，如：C://myPictrue//1.jpg
     * @param pressText 水印文字， 如：中国证券网
     * @param fontName 字体名称，    如：宋体
     * @param fontStyle 字体样式，如：粗体和斜体(Font.BOLD|Font.ITALIC)
     * @param fontSize 字体大小，单位为像素
     * @param color 字体颜色
     * @param x 水印文字距离目标图片左侧的偏移量，如果x<0, 则在正中间
     * @param y 水印文字距离目标图片上侧的偏移量，如果y<0, 则在正中间
     * @param alpha 透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)
    */
    public static void pressText(String targetImg, String pressText, String fontName, int fontStyle, int fontSize, int x, int y,
                    float alpha) {
        pressText(targetImg, pressText, fontName, fontStyle, fontSize, x, y, alpha, "jpg");
    }

    public static void pressText(String targetImg, String pressText, String fontName, int fontStyle, int fontSize, int x, int y,
                    float alpha, String ext) {
        try {
            File file = new File(targetImg);

            Image image = ImageIO.read(file);
            int width = image.getWidth(null);
            int height = image.getHeight(null);

            fontSize = width / ((2 * getLength(pressText)) == 0 ? 1 : (2 * getLength(pressText)));

            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bufferedImage.createGraphics();
            g.drawImage(image, 0, 0, width, height, null);
            g.setFont(new Font(fontName, fontStyle, fontSize));
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));

            int width_1 = fontSize * getLength(pressText);
            int height_1 = fontSize;
            int widthDiff = width - width_1;
            int heightDiff = height - height_1;
            if (x < 0) {
                x = 10;
            } else if (x > widthDiff) {
                x = widthDiff;
            }
            if (y < 0) {
                y = heightDiff - 10;
            } else if (y > heightDiff) {
                y = heightDiff;
            }

            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);


            g.setBackground(Color.BLACK);
            g.setColor(Color.WHITE);
            g.drawString(pressText, x, y + height_1);
            g.setColor(Color.BLACK);
            g.drawString(pressText, x + 2, y + height_1 + 2);
//          g.setColor(Color.WHITE);
//          g.drawString(pressText, x + 1, y + height_1 + 1);
            g.dispose();
            ImageIO.write(bufferedImage, ext, file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

检查传入file的format名称

    /**
    * 检查传入file的format名称
    * @param f 传入的文件
    * @return
    */
    public static String getFormatInFile(File f) {
        return getFormatName(f);
    }

    /**
     * 对文件进行format检索
     * .jpg .jpeg .jpe .jfif ===> JPEG
     * .png ===> png
     * .gif ===> gif
     * .
     * @param o
     * @return
     */
    // Returns the format name of the image in the object 'o'.
    // Returns null if the format is not known.
    public static String getFormatName(Object o) {
        try {
            // Create an image input stream on the image
            ImageInputStream iis = ImageIO.createImageInputStream(o);
            // Find all image readers that recognize the image format
            Iterator<ImageReader> iter = ImageIO.getImageReaders(iis);
            if (!iter.hasNext()) {
                // No readers found
                return null;
            }
            // Use the first reader
            ImageReader reader = (ImageReader) iter.next();
            // Close stream
            iis.close();
            // Return the format name
            return reader.getFormatName();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

获取字符长度

/**
     * 获取字符长度，一个汉字作为 1 个字符, 一个英文字母作为 0.5 个字符
     * @param text
     * @return 字符长度，如：text="中国",返回 2；text="test",返回 2；text="中国ABC",返回 4.
    */
    public static int getLength(String text) {
        int textLength = text.length();
        int length = textLength;
        for (int i = 0; i < textLength; i++) {
            if (String.valueOf(text.charAt(i)).getBytes().length > 1) {
                length++;
            }
        }
        return (length % 2 == 0) ? length / 2 : length / 2 + 1;
    }

图片缩放

    public static BufferedImage resize(BufferedImage source, int targetW, int targetH) {
        // targetW，targetH分别表示目标长和宽
        int type = source.getType();
        BufferedImage target = null;
        double sx = (double) targetW / source.getWidth();
        double sy = (double) targetH / source.getHeight();
        // 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放
        // 则将下面的if else语句注释即可
        if (sx > sy) {
            sx = sy;
            targetW = (int) (sx * source.getWidth());
        } else {
            sy = sx;
            targetH = (int) (sy * source.getHeight());
        }
        if (type == BufferedImage.TYPE_CUSTOM) { // handmade
            ColorModel cm = source.getColorModel();
            WritableRaster raster = cm.createCompatibleWritableRaster(targetW,
                            targetH);
            boolean alphaPremultiplied = cm.isAlphaPremultiplied();
            target = new BufferedImage(cm, raster, alphaPremultiplied, null);
        } else
            target = new BufferedImage(targetW, targetH, type);
        Graphics2D g = target.createGraphics();
        // smoother than exlax:
        g.setRenderingHint(RenderingHints.KEY_RENDERING,
                        RenderingHints.VALUE_RENDER_QUALITY);
        g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
        g.dispose();
        return target;
    }

    public static String resize(File file, int targetW, int targetH,String ext) throws IOException{
        BufferedImage source = ImageIO.read(file);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        BufferedImage bi = resize( source, targetW, targetH);
        ImageIO.write(bi, ext, baos);
        String result = new BASE64Encoder().encode(baos.toByteArray()).trim();
        return result;
    }

    /**
     * 统一比例压缩。
     * @param filePath
     */
    public static void resize(String filePath) {
        resize(filePath, finalX, finalY, false);
    }

    /**
     * 图片缩放
     * @param filePath 图片路径
     * @param height 高度
     * @param width 宽度
     * @param bb 比例不对时是否需要补白
    */
    public static void resize(String filePath, int height, int width, boolean bb) {
        resize(filePath, height, width, bb, "jpg");
    }

    public static void resize(String filePath, int height, int width, boolean bb, String ext) {
        try {
            File f = new File(filePath);
            BufferedImage bi = ImageIO.read(f);

            ImageIO.write(resize(bi, height, height), ext, f);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }